Struts 1.2 自定义标签步骤与实践

Struts 1.2 自定义标签步骤如下：

１. tld 定义 ：xx-security.tld
２. 写支持tag的java class  ： PasswordTag.java, 一般继承自 TagSupport （WriteTag 等）
３. （optional）在web.xml中配置标签库加载 1中的tag
４. 调用自定义标签的html

１. xx-security.tld 如下：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE taglib
        PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN"
        "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd">
<taglib>
    <tlib-version>1.0</tlib-version>
    <jsp-version>1.2</jsp-version>
    <short-name>xx-security</short-name>
    <description>
      <![CDATA[
   <p>
   This taglib contains tags used for some security features of xx.
   </p>
      ]]>
    </description>
    <tag>
        <name>applet-param</name>
        <tag-class>com.company.proj.web.taglib.security.ParamTag</tag-class>
        <body-content>empty</body-content>
        <description><![CDATA[
            <p><strong></strong></p>
  ]]>
        </description>
        <attribute>
            <name>name</name>
            <required>true</required>
            <rtexprvalue>true</rtexprvalue>
            <description></description>
        </attribute>
        <attribute>
            <name>value</name>
            <required>true</required>
            <rtexprvalue>true</rtexprvalue>
            <description></description>
        </attribute>
    </tag>
  
    <tag>
        <name>password</name>
        <tag-class>com.company.proj.web.taglib.security.PasswordTag</tag-class>
        <body-content>empty</body-content>
        <description>
           <![CDATA[
            <p><strong></strong></p>
           ]]>
        </description>
    </tag>
</taglib>
Note: 没有什么注意，只要按照格式写就好

２. 支持tag的PasswordTag.java

import java.io.IOException;
import java.io.Writer;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspTagException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.TagSupport;

 

public class PasswordTag extends TagSupport {  
 
private static final long serialVersionUID = 3174234039143531079L;
 
    @Override 
    public int doStartTag() throws JspException {
     HttpServletRequest request = (HttpServletRequest) pageContext.getRequest();

     Writer out = pageContext.getOut();
        try {  
            out.write("<input type=\"password\" size=\"20\" class=\"inputBox\" name=\"");
            out.write("password");
           out.write("\" value=\"");
           out.write("\">\r\n");
           out.flush();
  
        } catch (IOException ex) {  
            throw new JspTagException("Error lahh");   
      }  
        return EVAL_BODY_INCLUDE;  
}  

    @Override 
    public int doEndTag() throws JspException {
     
//     Writer out = pageContext.getOut();
//        try {  
//         out.write("\r\n");
//         out.write("Hello World,snow365bbb!");
//           
//        } catch (IOException ex) {  
//            throw new JspTagException("Error lahh");  
//        }  

//       pageContext.getSession().setAttribute("xx", XX);

        return EVAL_PAGE;  
}  

 
}
Note: 1)根据需要，重写doStartTag() doEndTag()
              2) pageContext.getOut().write()就是在页面输出html语言

３. 在web.xml中配置标签库加载。(这个不做，也没有问题，jsp 里面uri已经写明)
   <taglib>
        <taglib-uri>/WEB-INF/tld/xx-security.tld</taglib-uri>
        <taglib-location>/WEB-INF/tld/xx-security.tld</taglib-location>
</taglib>

4.页面调用
         <%@ taglib uri="/WEB-INF/tld/xx-security.tld" prefix="xx-security"%>
         <xx-security:password></xx-security:password>